McDonnell & Miller FS7-4SJ Snap Switch Refrigerant This 10-inch by 10-inch unit

This 10-inch by 10-inch unit utilizes an extruded aluminum frame and blades to ensure structural integrity and corrosion resistance within the plenum

this 24V DC steam coil provides the reliable electromagnetic force required for consistent valve actuation in demanding process heating systems

replacing a brittle or corroded harness with a Reznor 197199 Wiring Harness restores circuit continuity and prevents intermittent sequence-of-operation failures

this unit is IP66/IP67 rated for superior moisture protection in high-humidity environments

minimizing energy waste while maximizing static pressure performance

McDonnell & Miller FS7-4SJ Snap Switch Refrigerant This 10-inch by 10-inch unitThe McDonnell & Miller FS7 4SJ (Part Number 120171) is a rugged, industrial grade liquid flow switch designed for high pressure applications where standard brass units fall short. This SPDT snap switch features a durable stainless steel body and wetted parts, allowing it to withstand a maximum pressure of 1000 PSI. Built with a 1 1 4" BSPT connection, it is engineered for precise flow sensing in large pipe systems across hydronic heating, industrial